Integrated hydration and alkylation of gaseous olefins



United States INTEGRATED HYDRATION AND ALKYLATEON OF GASEOUS OLEFINSWalter P. Bloecher, Jr., Cranford, and David W. Young,

Westfield, N. L, assignors to Esso Research and Engineering Company, acorporation of Delaware Application October 14, 1954, Serial No. 462,201

6 Claims. (Cl. 260-641) This invention relates to the conversion ofgaseous olefins to a liquid fuel of balanced volatility and superioranti-knock characteristics. More specifically, it relates to a flexiblecombination process wherein a C C olefin-containing light hydrocarbonfeed is catalytically converted to a high octane liquid motor fuel intwo stages, first being partially hydrated to produce an oxygenatedmotor fuel while the unconverted remainder is alkylated in a subsequentstage to produce gasolinerange hydrocarbons. It also relates to the fuelcompositions produced in the process.

In the blending of motor gasoline the quantity of high volatilitycomponents which can be included is limited by specifications which arebased on Reid vapor pressure and the percentage distilling below 158 F.If these specifications are exceeded, the undue front-end volatility ofthe gasoline blend tends to cause vapor lock in the combustion engine.Consequently a surplus of propylene, butanes and butylenes is usuallyavailable at most refineries and must be either disposed of in lowpricedproducts such as fuel gas or must be converted into a less volatilegasoline blending stock. Such upgrading has been heretofore accomplishedmostly by cata lytic polymerization of the C -C olefins. However, thishas not constituted a fully satisfactory use of available light endssince such polymerization makes no use of saturates and the resultingpolymer possesses only a moderately good motor octane rating whereaswith the advent of automatic transmissions motor octane specificationshave been becoming increasingly critical. Therefore, a real need hasdeveloped for a refining process capable of producing a gasoline blendhaving a high motor octane rating while making economical use ofavailable light ends.

It is well known that olefins such as propylene can be directly hydratedin the presence of suitable catalysts such as phosphoric or sulfuricacid or tungstic oxide, to produce oxygenated products such as alcohol,acetone and ether, all of which greatly improve the motor octane ratingof gasoline blends when added thereto. However, such addition alsoresults in an increased volatility of the gasoline so that compensatingamounts of inexpensive butanes and other light naphtha constituents mustbe left out of the blend. Consequently, the addition of the oxygenatedhydration products may result in a substantial increase in cost of theblended gasoline product and further aggravates, rather than relievingthe problem of properly utilizing the surplus light ends. This lightends surplus may become particularly troublesome 2,8215% Patented Mar.18, 1958 in the summertime when a relatively less volatile gasoline isrequired. Furthermore, the hydration of propylene is in itself ratherdiflicult to accomplish and accordingly requires feeds having as high aconcentration of the olefin as possible. But since conversion tends tobe rather low and so usually makes stage-wise conversion of unreactedfeed imperative, the latter must be purified or separated from thehydration products before it is further hydrated.

It is also known that a premium grade gasoline component can be obtainedby alkylation in which olefins such as propylene, butenes or pentenesare combined with isoparaflins such as isobutane or isopentane. Suchalkylation can be done thermally at high temperatures and very highpressures, but is preferably done at low temperatures in the presence ofcatalysts such as concentrated sulfuric acid, hydrofluoric acid,aluminum chloride or boron trifiuoride. Such catalytic alkylationproceeds quite readily and, as long as a suflicient excess of the C 01'.C isoparaflin is present, results in substantially complete conversionof the olefinic feed constituents into valuable C to C branched chainparaffins of high anti-knock value and relatively low volatility.

Heretofore, however, when a refinery was required to rely upon suchalkylation to any great extent for the purpose of raising the octanelevel of gasoline, a critical shortage of necessary pressurizing stockstended to develop. This resulted from the fact that the alkylate producthad such low volatility that it had to be supplemented by substantialamounts of butanes to give satisfactory start-up characteristics, butthe alkylation itself consumed a large proportion of isobutane from thelight ends pool normally available for pressurizing. Consequently, theadoption of alkylation in the production of motor fuel has not alwaysbeen economically attractive, despite its intrinsic merits. On thecontrary, because of the excess supply of olefins with respect toavailable butanes, notably isobutane, alkylation has been heretoforelimited largely to the most desirable olefins, namely the butenes,although C and C oiefins can also be ailcylated to give a superiorgasoline constituent. Moreover, even the alkylation of butenes has oftenresulted in upsetting the volatility distribution of a given gasolinepool. Here again, the fact that the gasoline product is normallyrequired to meet substantially different volatility specifications inthe summer than in the winter has represented an additionalcomplication.

It is the main object of the present invention to provide a flexibleprocess for the conversion of light ends, and especially propylene, to ahigh quality blending agent, the volatility of which can be readilyvaried to meet operating needs. Another object is to convert C -Chydrocarbons to compounds suitable for increasing the motor octanerating of gasoline blends without upsetting their volatilityrequirements, particularly in the blending of motor fuels havingresearch octane num bers of 96 to 100 or higher and ASTM motor octanenumbers in the range of about 83 to 100, and especially those havingmotor octane numbers between about 85 and or higher. A more specificobject is to hydrate and alkylate a propylene feed substantiallycompletely in an integrated process whereby liquid fuels having asuperior octane rating and balanced volatility are produced, with aminimum of recycling or handling of inert diluents. A still furtherobject is to hydrate gaseous olefins in a non-corrosive system toproduce oxygenated products suitable as motor fuels, and to achievesubstantially complete utilization of the feed with a minimum ofrecompression and purification. Still another object is to provideblending stocks suitable for raising the volatility and octanecharacteristics of other streams which may include virgin naphtha,thermally or catalytically cracked naphtha, hydroforniate, and so forth.These and other objects as well as the general nature and operation ofthe invention,'will become more clearly apparent from the subsequentdescriptionand accompanying drawing.

It has now been discovered that light olefins can be essentiallycompletely converted to valuable gasolinerange constituents ofb'alanced, predetermined volatility in a surprisingly efiective manner.This is done by first passing-the olefin-rich feed through a catalytichydration step and then completing the conversionlby alkyla tion of theunconverted olefins. Furthermore, a combination process particularlyadapted to optimum ntilizaa tion of propylene and C hydrocarbons willinclude direct hydration of propylene, propylene/butylene alkylation,and polymerization of butylenes. According to the present inventionthese individual processes are combined and integrated so' as tocomplement each other in maintaining a flexible and unusually effectivebalance among the several reactants, especially propylene, butylenes,and

isobutane, and in maximizing conversion of propylene.

Unless otherwise indicated, all ratios and percentages stated in thesubsequent description and claims are on a weight basis. a I

Useful as hydration feeds in the present process are refinery streamscontaining about 30 to 100 mole percent of a C and/or C olefin,'whichmay further con tain minor amounts of ethylene and higher olefins,usually in'addition to at least 5 mole percent of inert gases such ashydrogen, methane, ethane, propane, bu-

tanes, nitrogen, carbon dioxide, etc. The preferred olefinic feedto thehydration stage is a C hydrocarbon cut consisting essentially of about70 to 95 mole percent propylene and correspondingly 30 to 5 mole percentpropane, that is, a cut containing about 2.3 to 9 moles of propylene per'mole of propane. Another likely feed may be a C -C cut containing amixture of propylene and butylenes together with propane and butanes,and usually also some ethylene. preferably first purified to removesulfur compounds,

notably hydrogen sulfide, e. g. by washing with diethanol amineor asimilar organic base. Alkaline compounds and heavy oils may. alsodesirably .be removed from the feed in any known manner and suchpurification steps do not as such fo'rrn a part ofthe present invention.

'In the direct hydration step' the OICfiH-I'lCh 'fCBd is mixed with 0.2to 5 moles, preferably lj to 2 moles, ofwate'r per mole of olefin. Themixture is then passed over any suitable solid or liquid hydrationcatalyst, preferably of the 'low acid, non-corrosive type suitable foruse in regular steel equipment.

containing about 40% of phosphoric acid baked into a solid support suchas kiesel guhr, clay, silica gel, alumina, titania, char coal, coke,activated carbon, and the like..

In most cases the feed isv 7 Accordingly, the; catalyst may be of theso-called modified UQP type condensate and steam for removing the heatof reaction.

Hydration conditions may include pressures of about 500 to 5000 p. s. i.g., preferably 800 to 1500 p. s. i. g., and temperatures of about 120 to300 C., preferably 200 to 235 C. Above about 235 C. the selectivity tohydrated products may decrease fairly markedly at the expense of polymerformation. The hydrocarbon feed is usually present in the reaction zoneas a supercritical mixture. Conversion varies essentially indirectproportion to pressure. The reaction is carried out with spacevelocities of 0.5 to 5 volumes of liquid olefin feed per volume ofreactor per hour, velocities of 1 to 3 v./v./hr. being preferred. Atthese velocities about to 70%, e. g. 30% of the olefin present in thefeed can be readily converted to a liquid mixture of alcohol, ether,some liquid polymer of gasoline boiling rangaansusuan also some ketone.-Suchamixture will have a research octane number of about 110 to 112 to.116 unleaded, 'a-

motor octane number of about 93, a specific gravity of about 0.71 to0.75 and an atmospheric boiling range essentially between about 50 and95 C., though it may uable, clean burning fuel which is suitable for use'in Other suitable catalysts include adipic, maleicor simi-f lar organicdibasic acids, adsorbent silica-aluminia gels of the type commonly usedfor catalytic cracking, silver sulfate, as well as copper sulfate orphosphate or copper pyrophosphate of the type heretofore used-inpoly-men .Another suitable catalyst is reduced tungsten zation.;

pentoxide... v s. p 7 The hydration reactor may be-a'heat-exchang ertypeof vessel consisting of catalyst-filled tubes'jacketed by reactor. I

separated from the. unconverted feed by cooling the hydration Zone.efiluent so as to form a waterflayer and either aviation or motorgasolines. Such a hydration product, on an anhydrous basis, willnormally contain about 55 to 96 volume percent of alcohol, 3 to 35volume percent ether, 0 10 V10 volume percent acetone, and, about 1 to25' volume percent polymer.

The unconverted hydrocarbons withdrawn from the hydration step willcontain about 15 to 70 mole percent and preferably only about 20 to 50mole percent. of

propylene or C .C olefin. The reaction mixture from; t l the hydrationstage is desirably first passed through a frac tionating column Wherewater and thevaluable hydrated products are Withdrawn as a liquidbottoms fraction and only the unconverted feed mixture containingprimarily the olefin diluted with paraffins or other inert gases is 7taken overhead and passedto the alkylation stage unit. The previouslymentioned fractionating column or stabilizer is operated an suitablepressure, e. g. 200 to 400 p. s. i. g., and the .olefinic overheadstream is condensed to permit its being pumped to the second-stageAlternatively, the hydrated products can be a hydrocarbon layerseparable therefrom.

7 In the alkylationstep the unconverted .olefin'is combinedwithanisoparaflin-containing C, or C streamsuchas abutane-butylenes st reamcoming from, a C catalytic polymerization plantand normally containing50 to isobutane. Thecombined a lkylation feed is of such com positionthat the. i'soparafiin contained therein, e. g. isobutane, is sufiicienttoalkylate the olefin, after incurring any processing losses. As 'aminimum, for instance, the

feed to the alkylation plantshould contain 1.6 volumes,

of isobutane per volume of propylene, or 1.2 volumes of isobutane pervolume of butylenes. An isoparaffin/olefin ratio in the total reactorfeed of about 3/ 1 to 10/1 is desirable, a ratio. of about 8/1 beingpreferred. Considerably higher. isopa'rafiin/olefin ratios are normallymaintained in'the. reaction zone proper, ratios of about 150/1 to 1000/1, e. g. 2507.1, being suitable. The alkylation may be catalyzed in aconventional manner, e. g..

by mixing with sulfuric acid of about 88 to 98% strength.

Such an alkylation maybe. conducted in the acid phase of the resultingoil-acid emulsion, maintained at about 30 to 70? F by refrigeration. Asis. otherwise well known, the .heat of reaction can be removed from anemulsion recycle, the volume of which is large relative to the freshfeed. For instance, an emulsion/olefin volume ratio of 60/1 to 100/1 isadvisable. Recycling of the emulsion also provides the energy requiredfor mix= ing the contents of the reactor to maintain the emulsion and toeliminate localized concentrations of olefin. The reactor pressure issufficient to maintain a liquid phase, e. g. 100 to 200 p. s. i. g. Theemulsion will consist of 20 to 60% acid by volume, and operations willbe maintained so that 40 to 70% by volume of the oil phase will beisoparaffin, the remainder being alkylate, normal parafiins and olefins.Acid strength in the reactor is maintained by fortifying it with 98%acid and withdrawing a corresponding amount of weaker acid from theprocess.

A portion of the emulsion recycle may be diverted to an acid settler.The oil phase from this vessel is preferably caustic washed and fed to atower which will remove and purge any residual light hydrocarbons. Sincethe conversion of olefin in the alkylation plant is essentially 100%,the purge will normally be free of olefin. The bottoms, consisting ofisoparafi'in, normal paraifin and alkylate are fractionated further. Theisoparaffin is split out in a deisobutanizer column and recycled to thealkylation reactor while normal butane is taken overhead in adebutanizer tower, mixed with any by-passed C streams, and sent togasoline blending for vapor pressure control. Since alkylate and normalbutane are remixed in the final gasoline blend, the debutanizer can bebypassed entirely if the combined product happens to meet volatilityspecifications for motor fuel. The alkylate bottoms from the debutanizertower may then be rerun to a 330 F. endpoint overhead suitable foraviation gasoline, a 430 F. endpoint sidestream for motor gasoline, anda +430 F. bottoms for heating oil.

Of course, instead of using the sulfuric acid emulsion system described,the alkylation may be conducted in a variety of other ways withoutdeparting from the present invention. For instance, gaseous catalystsuch as boron trifluoride, other liquid catalyst such as hydrogenfluoride, or a solid catalyst such as aluminum chloride mayalternatively be used in suitably modified alkylation processes whichare otherwise well known.

In accordance with the preferred embodiment of the invention the processalso contains a catalytic polymerization step for maximum versatility.Such polymerization may be of the UOP-type using a tubular reactorpacked with a catalyst consisting of kieselguhr impregnated withphosphoric acid. Alternatively, California-type polymerization may beused in which phosphoric acid on quartz chips is placed in a tower-likevessel cooled by recycle quench streams. Both types of plant operate atabout 300 to 450 F. and at elevated pressure, e. g. 1000 p. s. i. g. Thefeed to this unit is an olefinic stream in the C C hydrocarbon range, e.g. a refinery C stream containing 20 to 60% butylenes with 20 to 50%isobutane, preferably washed with caustic soda and water. Propylene mayalso be fed to the polymerization unit, especially in the summer timewhen a motor fuel of relatively low volatility is required. Thepercentage of olefins converted in the polymerization stage can bevaried from to 95% either by varying reactor conditions or by bypassingthe reactor. Olefin polymer, unreacted olefin, and saturatedhydrocarbons can then be separated in a suitable fractionation tower, e.g. at 150 to 200 p. s. i. g. pressure, from which the polymer is removedas bottoms. The overhead may then be sent to gasoline blending and tosupply the isoparafiin to the alkylation stage as required.

A specific operation illustrative of the present invention will now bedescribed with reference to the schematic flow plan shown in Figures 1and lA of the accompanying drawing. In the illustrated embodiment alight olefin feed is hydrated and alkylated in sequence, in combinationwith an olefin polymerization step which further helps in balancingproduct volatility and thus further increases the flexibility of theprocess.

Referring to the drawing, the equipment shown is subdivided into threeprincipal sections: a catalytic hydration plant'and a catalyticpolymerization plant, both of which are shown in Figure l, and aconnected alkylation plant shown in Figure l-A. Two hydrocarbon streams,both being obtained from a C C cut from a catalytic cracking plant, arefed to this combination of units. One stream is a C stream consistingessentially of about 65 mole percent of propylene and 35 mole percent ofpropane, desulfurized by scrubbing with diethanolamine; and the other isa caustic and water washed 0.; stream consisting essentially of about48.5 mole percent isobutane, 8 mole percent normal butane, 16 molepercent isobutylene and 27.5 mole percent of normal butylenes. Theentire C C cut from which these two feeds were obtained contained about42.5 mole percent of C hydrocarbons and 57.5 mole percent of the Chydrocarbons.

Referring to Figure l, the C stream is liquefied and fed to thehydration plant via line 1 to depropylenizer tower 2. This tower isoperated at 300 p. s. i. g. and splits the feed into an olefinconcentrate consisting essentially of mole percent propylene and 10 molepercent propane, and a bottoms product consisting essentially of 90 molepercent propane and 10 mole percent propylene. The bottoms stream iswithdrawn from the system via line 3 and can be used as fuel or finishedto commercial liquefied petroleum gas. The propylene concentrate isremoved from tower 2 via overhead line 4, condensed and mixed with 1.5moles of water of hydration per mole of propylene. This water isintroduced via line 7. The liquid mixture of olenfinic feed and water ispassed through line 9 into hydration reactor 10. This reactor is aheat-exchange type vessel as previously described, the vertical tubes ofwhich are packed with a pelletized hydration catalyst consistingessentially of reduced tungsten pentoxide prepared as described inBritish Patent No. 622,937 (1949). The reactor is kept at a temperatureof about 225 C., the heat of reaction being removed by cooling waterwhich is circulated through and evaporated in the cooling jacket whichsurrounds the reactor tubes. The reaction pressure is maintained atabout 1700 p. s. i. g. The hydrocarbon feed is passed into tower 10 at aspace velocity corresponding to about 0.5 volume of cold liquid feed perreactor volume per hour. A conversion of about 40% of the olefin feed isobtained, yielding a mixture of isopropanol, diisopropyl ether, liquidpolymer of gasoline boiling range, and a small quantity of acetone.

The wet crude reaction product is withdrawn from the hydration zonethrough line 11, throttled through a valve 12 to a pressure of about 300p. s. i. g. and fractionated at that pressure in stabilizer tower 15.Here unreacted propylene and propane are taken as a liquid overheadstream 16 while the hydrated olefin and unreacted water are taken asbottoms through line 19.

Tie-ins are provided between stabilizer overhead line 15 anddepropylenizer feed line 1 and reactor feed line 4. This permitsrecycling unconverted propylene from line 16 through line 17 back tohydration reactor 10, or conversely, if more propylene is available thanis required for hydration, surplus olefin may be diverted around reactor10 from line 1 via line 17, or from line 4 via lines 14 and 17. Anyunhydrated propylene finally leaves the hydration plant as stabilizeroverhead via line 16 and is fed to the alkylation plant as hereafterdescribed.

The stabilizer bottoms 19, consisting of water and hydrated product, isfed to finishing facilities for removal of water. This may beaccomplished by a series of two or more azeotropic distillationsconducted at different pressures so as to break the azeotrope formed inthe preceding distillation stage. Alternately, as illustrated in thedrawing, water may be removed by azeotropic distillation in dewateringtower 20 followed by caustic treatment.

Tower 20 separates the crude hydration product into water bottoms and anazeotropic distillate containing about-91%- organic liquid and- 9%water. Thenvater bottoms separated in tower -20,-is' sent tojthe sewervia line 22 while the az eotropicdistillatefil is made essentiallyanhydrous by scrubbing in, causticcontactor 25.w ith a 50% aqueouscaustic .soIution introducedthrou'gh line 26. Dilute caustic solution.is withdrawn-.yia linef28.

The final product is-taken as an overhead stream 31 from steamevaporator 30 to remove, any residual caustic and will contain 3% or-less water1 by volume. ffFoninstanee, a; typical dry- 'productmay b'oilbetween about 5 and,

92 C; at 760--mm.* Hg and'consist' essentially of "85% isopropylalcohol, 5'%* diisopropyl emery-2% acetone, 5%: polymer and 3 water;allon a-volume basisig This com For instance, during winter operations-when high-vola-' tility is desired, thepropylene'may berecycled throughthe hydration plantto extinction, resulting in a hydrated productyield-of about 82%. -In-the summer time when gasoline volatility isto'bekept fairly-low, the'hydration plant may best'be operated onaonce-through basis, re-- sulting in'a hydrated-product yield of about24% based on propylene feed. a a g If desired, vthehydration-product canbe used directly as a motor fuel, butpreferablyit will be blended withvarious hydrocarbon base stocks boiling inthe gasoline range. Such basestocks,"it is =well known, maycontain virgin naphtha, thermally orcatalytically cracked gasoline, reformed orshydroformed naphtha,polymer. gasoline, hydrocodimer, or..variousmixtures thereof.Furthermore,.in accordance with the present invention itis particularlyadvantageous to balance the-increased volatility dueto'the. hydrationproduct by blending in a suitable amount of alkylate .producedin alaterdescribed part of the present process. Typically, the gasoline basestocks may:have: a clear research octane rating of about 85 tov 103,usually between about-85 and 90 in the case of motor fuel, and a motoroctane rating (leaded) ,which may range from about85 in summer to 100 inWinter. Of course, usual anti-knock agents,=e. g. 1 to 5' cc. oftetraethyl lead per gallon, other additives such as'laurylp-aminophenol, 4-methyl-2,6-di-tert-butyl phenol or other anti-oxidants,gum-inhibiting agents, phosphorus containing surface ignitionlinhibitorssuch as tricresylphosphate or chloropropyl,thionophosphate, and otherconventional materialsmay: also be added. Ofecourse, instead. of'

blendingthe hydration product into gasoline, it .canalso beaddedtodiesel fuel; e. g. to improve itscoldstarting properties.

The other main feed tothe process is. a C stream from a catalyticcracking, unit. This stream maycontain, as an example, 55% butylenes,36% isobutane and 9% .normal butane. stream is fed via line 41 to atubular UOP type polymerization reactor 40 filled with a catalystconsisting essentially of kieselguhr impregnated with phosphoric acid.This reactor is operated at about 1000 p.;s. i. g. and 380 F. A butyleneconversion of about .70 %;;isuobtainedin reactor 40. However, ifdesired, a'lower overall conversion of butylenes can be obtained bydiverting butylenes from line 41 around reactor 40 via by-passline Aftercaustic and water washing this C 42. Of course, lower or higherbutylenes conversion can 7 a C to 430 F. butylene polymer is removed asbottoms via line 46. Butylenes and butanesare taken as anoverheadproduct 47 and, after mixing With,by-passedreactor feed 42, ifany, sent to gasoline blending and the alkylation plant as required. Forinstance, referring tov Eigurej 1;- -A, an'increased am'ountoffthe' C,out can be sent via line 481 gasoline blending when 'C h'ydrocarbons arein relatively, short supply with respecttothe vaponpressure requirementsotthe gasoline product pool; Conversely;

when' 'Cghydrocarbons are in longsupplyaall or most of thefC cut fromthe polymer plant issent' through line 49 tothealkylation, plantandlittle or noneis. withdrawn throughline 48. '"In such cases any needfor'raisingthe vblatilityofthegasolinepool'carr be satisfied by; usingthe normal butane separated inthe alkylationplantas' hereafter;described.

Again referring'to Figure the feed tothe alkylation' reactor maycomprisethe; butane-butylenes stream;

49 from thepolymerization plant, ,the; propylene-rich stream 16'fromthe-hydrationplant" and a ,stream .57

of-9 8%- sulfuric acid-which -serves as a catalyst. For example, in-thesummerthe C stream 49 may; contain about' 82.7 vol.-percent isobutane,-13.7 1 vol. percent nbutane and 3.6-vohpercent-butylenes, and C stream-16 may contain about 86.3 vol.- percent propylene and 1317 The combinedfeed inline 61 is volume of'C; hydrocarbons, or specifically about0.78/1- for the particular example-given. On' the other hand,nopropylenewill normally betsentto alkylation in winter.

Consequently, the: alkylation feed will consist of'the C stream49v.which thenzmay be somewhat leaner in -isobutane, e. g.', it maycontain- 50 vol. percent isobutane, 8.4 .vol. percent n-butane, and41.6%; butylenes. Freshacidis addedto the hydrocarbon feed attabouttherate at whichitis. consumed, that. is, about 1 to 1.5: gals/gala Themixture is maintained inreactor in liquid' olefin. phaselatebolutl 35"..F.. anda pressure .of' 150.p..-'s. ieg. Heat. of reaction .is removed,by refrigeration from.emulsion recycle,line,63 .which,passes throughheat exchanger 62 at arate Oi about 100 volumes of emulsion per volume;of olefin feed. Theemulsion consists of. about 50%. acid' by volume.The, oil phase of the emulsioncontains about 55 iso but ane by volume.

A fraction equal to about 3 to Spercent ofthe emu1-. sion is divertedfrom recyc1elinel63 vialine 64 to acid settler 65. Here ;the spent.acid. layer is removed via line 67, while the oilphaseis, removedvia-line 68 and washed in scrubber 69-with strongcaustic introduced vialine66. 1 After settling in tank 70 the spent caustic is discarded via.line, 71 while, thescrubbed oil phase is sent viai rline 72togstabilizertower 75. There any residual C hydrocarbon, that is,essentially pure propane, is removed and sent via:line 76 for .use. inliquefied petroleumgas. ,The' bottoms from depropanizer tower 75, arepumped jvia .'line 78. to deisobutanizer tower .80where;isobutane;;isysplit out and, recycled. vialine 81zto alkylation,reactor; 60. The bottoms ,frorn tower are pumped via line 83 to,debutanizer towera85awhere-nor-.

mal-butane issplitout andsent :via line 86 to gasoline blending forvaporpressure control. Where necessary, someofi this normal butane mayalso be. isomerized to increase the supply of isobutane required in thealkyla tion. The alkylate bottoms stream 87 from the de-' butanizer -maythen, be rerunin tower'90. .There a light alkylatehaving a 330" F.endpoint suitable for aviation gasolinehisproduced asanoverhead stream91, a heavy alkylatehaving a 430,F. endpoint suitable for motor gasolineis'removed vialine 92,. and. alkylate bottoms. suitable :for heating'oilare removed-via line 93. ,Of course, since alkylateuandnormalbutanerare. -eventually remixed inthefinalg soline blen eua kyl e debuanizer 85 can be partially or entirely bypassed via line 84, if

line will have a clear research octane number of about 7 92 to 93 and amotor octance number of about 90.

EXAMPLE The products of the present invention can be used forformulating various gasoline blends which will meet the customaryvoatility specifications with respect to both Reid vapor pressure andpercent distilling at 158 F. Thus, Tables I and II illustrate winterandsummergrade gasolines, respectively, formulated by blending all ing aWide variety of specifications.

of the various products of the novel combination process.

Table I WINTER-GRADE GASOLINE Vol/100 vol. Composition Total 03-04 ofBlend,

Feed Vol. Percent 0 Hydration Product 25. 3 35. 6

C Alkylate 0 0 Ca Polymer.- 0 0 O4 Alky1ate.. 38.1 53. 6 C4 P0lyrner 2.1 3.0 Isobutane 0. 9 1. 3 Normal Butane 4. 6 6. 5

Total 7l. 0 100. O

Anti-knock qualities of gasoline:

CFR Research Octane Number (with 2.6 cc.

tetraethyl lead) 105.5 ASTM Motor Octane Number (with 2.6 cc.

tetraethyl lead) 98.9

Table I shows that the novel process can be adjusted so that the entirefeed is converted into gasoline constituents which, upon being combined,produce a gasoline blend which has excellent anti-knock properties andpossesses enough volatility to satisfy winter requirements. 71 volumesof gasoline product are obtained in this manner per 100 volumes of C -C.feed, the difference in volume being due to the fact that the product isconsiderably denser than the light hydrocarbon feed.

CFR Research 0. N. (with 2.6 cc. tetraethyl lead)- 103.1 ASTM Motor 0.N. (with 2.6 cc. tetraethyl lead) 88.9

Table II shows a product obtained from essentially the same feed in analternative operation. Here the combination process was operated so asto convert the feed into a gasoline blend of excellent anti-knockcharacteristics and sufiiciently low vapor pressure suitable for summeruse.

By comparison with Table I it will be observed that, to meet summerspecifications, it is desirable to hydrate only a minor proportion ofthe propylene while alkylating most of it. Some butylenes are alsoalkylated to reduce volatility further. The remaining C and C olefinswhich cannot be alkylated because of insufficient isoparaflin are thenconverted into gasoline by polymerization. Conversely, to meet winterspecifications, most or all of the propylene can be diverted to thehydration step while being replaced in the alkylation step withbutylenes so as to make full use of the isoparafiin available. In eithercase the polymerization step serves as a kind of fiy wheel which keepsgasoline production at a maximum by utilizing the olefins leftunconverted in the hydration and alkylation steps.

Tables I and II illustrate the unusual flexibility of thenovel processin that they demonstrate that this process is entirely self-sufiicientto produce gasoline blends meet- Thus, gasolines can be produced whichhave Reid vapor pressures of about 7.5 to 13.0 p. s. i. g. anddistillation characteristics such that l8'to about 60 percent will bevolatile at 158 F. Such gasolines may contain, for instance, about 5 to36 volume percent of the hydration product, about 2 to 40 volume percentof gasoline-range polymer of a C C olefin, about 35 to 60 volume percentof an alkylate having 7 to 8 carbon atoms per molecule, and about 5 to10 parts of butanes. Of course, the process can also be operated inconjunction with conventional refining operations. In such a case thefinal gasoline blend may contain various amounts of extraneousconstituents such as virgin, catalytic and reformed naptha, the processof the invention being operated under conditions adjusted to satisfy thevolatility specifications of the final blend while maximizing theparticularly desirable constituents such as hydration product andalkylate.

In summary, the foregoing shows that the main value of the integratedprocess lies in its ability to provide maximum yields of products whichare very high in certain critical motor gasoline inspections, notablyoctane number and volatility. Furthermore, the integrated process isunusualy flexible and thereby adapted to meet fluctuations due toseasonal product quality requirements or available feed supply.According to this invention superior products are obtained from thelight ends which are available in any normal fuel products refinery,particularly in one which includes catalytic cracking facilities.

Secondly, the integrated process is valuable in that it providescompensations for certain limitations which characterize the severalcomponent steps individually. For instance, the relatively highvolatility of the hydration product tends to offset the relative lack ofvolatility of the alkylate, thereby making more paraflins available forvaluable alkylate production. The relatively poor octane blending factorwhich normally characterizes polymer gasoline is kept to a minimum sincein the present invention polymerization can be largely or even totallyreplaced by hydration which produces a fuel component of greatlysuperior blending value. Polymerization is used here only as a means ofcontrolling the isoparaffin/ olefin ratio for alkylation. Where surplusolefins can be used elsewhere, the present process need not contain anypolymerization step at all.

Finally, the drawback of low conversion which normally characterizesolefin hydration is overcome in the integrated process in that thedesired conversion is completed in the efficient alkylation stage,rather than attempting to complete conversion by recycling to thehydration stage. mizes conversion in a particularly advantageous manner.In addition, the process has an advantage in that the olefin feed whichis sent to alkylation from the hydration step contains a greaterconcentration of olefins than a catalytically cracked C cut ordinarilyused for alkylation.

The characteristics of the individual stages of the process aresummarized in Table III.

Consequently, the present process maxi-.

gamed T ableIlI LIGHT ENDS C QNV ERSIO N' Process Catalytic-Polymerl-'DirectHydration' Alkylatlon V ,.zation 5 7 Olefin Feedstock Cr Ca Ca?.,C4".. 7 Maximum conversion-percent on olefin feed. 95 -50 100 ,100.Other Feedstocks 7 N n .-Nm1 10 104; Products .Motor Gaso. Poly.;.Propylene bydra- Light alkylate; Heavy alkylate;

C4 stream of variable olefin content 63-55%).

tion product plus able olefin con- Alkylate Btms; i0 concentrate;

stream of varin0 concentrate.

tent (IS-90%).

, Ct- Polymer CtHydr. Product 7 Ca' Alky. Cr Alky.

Motor Gasoline Quality: 7 a i r Efleetive Blending RVP, p. s. i. g 1.519.2 2.5. Proportion Distilled at 158 F. (D+L) -6 134 .0 .0.

Percent. Research,Blending No. a

(clear); 72;101'.2.0N--.- '70; 99.5 ON 63:92.2 ON 65.1; 94.5 ON. (+2.6cc. TEL) 76; 103.8 0N 79;.1051 ON 73; 102.3 ON 74.3; 102.9 ON. BlendingASTM Motor ON V (clear 83- .6.

(+2.6 cc. TEL) 86 94. Vapor Lock Constant 2 0 1 Reid vapor pressure.Vaporlock constant C'.=.(5 RVP+percent distilled at 158 F.).

It can be seen that catalytic polymerization reacts olefinsonly, over awide range of conversions, to a relatively nonvolatile gasoline stock ofgood research but only fair motor octane number. Substantially completeconversion of the olefins canbe achieved. This affords a convenientmeansof completely utilizing the olefins as far as they cannot be used up inthe other steps of the. process. Also it is an effective way ofpreparingan isoparaflin concentrate suitable for alkylation.. Ifdesired, the:resulting isobutane or. iscpentane content offlth'econcentrate may be further increased by isomerization;

The direct hydration of propylene and/0r butylenes high totalconversion.

Table IV 'CONTROL OF GASOLINE QUALITY Origin of Gasoline CaseNo.1-Process of Invention Only Case No. 2-Process of Invention plusConventional Practice Desired Increase In-.- Research Octane NoPrlmarylcontrol Diverting olefin feed-from alkylation to hydration.

Secondary Control Conventional Control.

Tetraethyl lead concentration. Usually also reformation topolymerization.

. ing or hydroforming. Motor Octane No Divert Olefin feed from Divertolefin from polymeri- Do.

' ,alkylation to hydration. zation to alkylation. Volatility .Dlvertpropylene from alky- Divert butylenes from poly- Divert C4 hydrocarbonsfrom V I lation-tohydration. Also menzatiori to, alkylation. conversionsteps to gasoline divert Cr hydrocarbons Also propane can be blending.Also thermal from alkylationtogesoline blended into gasoline ifreforming or heavy virgin blending. no 0 hydrocarbons are naphtha.

* j available.

.lCf/olefin balance to alkylation plant- Divert propylene from alkyl-.Divert butylenes from alkylation' to hydration.

reactsithe olefin only, and to a limited degree. The resultingproductthas good research octane and superb motor octane quality.However, due to azeotropic effects, it is highly volatile. inadmixturewith hydrocarbon gasoline components, andthis effect must becounter jHaving described thefjgeiierfa natufnandflspecific-zexamplesillustrating the invention,---itwill-be"un'derstood that the latter. canbe mbdifidIinivafioiisfwayswithout: departingfrom'the scope and spirithereof. The novelty of'the present invention is particularly pointed outin the appended. claims. 7

'What'is claimed is: v V a 1. 'A process 'for converting a hydrocarbonfeed supply ofrc andtC paraffins, andolefins into gasoline components ofvariahlefpredetermirie'd' volatility and good anti-knockcharacteristics, which. comprises segregating from, said. feedhydrocarbonsan olefin-rich C fraction containin'gl70 to 95 propylene anda"C fraction containing butylenes and isobutane, feeding at least aportionof said olefi n rich ,C fraction and water of hydration dnto'ahydration 'zone' containing" a hydra tion i catalyst under conditions:conducive- .to producing an grated process, four major variables mustbe considered: oxygenated liquid boiling principally between about 50and 95 C., recovering said oxygenated liquid and an unconvertedpropylene-containing fraction, recycling a portion of said unconvertedfraction to said hydration zone, thereby adjusting the ratio ofunconverted propylene to propylene converted to oxygenated liquid,passing a sufficient portion of said C fraction through a polymerizationzone containing a polymerization catalyst under conditions conducive tothe formation of gasolinerange polymer to thereby adjust the butylenecontent of the remaining unpolymerized C fraction such that theisobutane present therein is just about sufiicient to alkylate all theremaining unconverted olefin, recovering said gasoline-range polymer,feeding said unpolymerized C fraction and all the unhydrated C fractionto an alkylation zone containing an alkylation catalyst under conditionsconducive to converting said fractions into an alkylate of which atleast 90% boils between about 50 and 220 C., recovering said alkylate,and controlling the quality of the resulting gasoline components byincreaseing the ratio of hydration zone olefin feed to alkylation zoneolefin feed plus polymerization zone olefin feed when increased productvolatility is desired, and by decreasing said ratio when decreasedproduct volatility is desired.

2. A process according to claim 1 wherein butylene polymerizaton isincreased in relation to butylene alkylation as propylene alkylation iscorrespondingly increased in relation to propylene hydration, in orderto reduce product volatility, and wherein butylene alkylation isincreased in relation to butylene polymerization as propyl- 14 enehydration is correspondingly increased in relation to propylenealkylation, in order to increase product volatility.

3. A process according to claim 1 wherein substantially the entire Cfraction is passed through the hydration zone and as much of theunconverted propylene from the hydration zone is mixed with the Cfraction as will produce a mixture having a proper isobutane propyleneratio for feeding to the alkylation zone while remaining butylenes arefed to the polymerization zone.

4. A process according to claim 1 for producing a relatively volatilecombination of gasoline components, which comprises convertingsubstantially all available propylene in the hydration stage.

5. A process according to claim 1 wherein the hydration catalyst isselected from the group consisting of phosphoric acid catalyst, activesilica gel catalysts and reduced tungsten pentoxide catalysts.

6. A process according to claim 1 wherein said a1kylation catalyst isselected from the group consisting of 88-98% sulfuric acid, hydrogenfluoride, boron fluoride, and aluminum chloride.

References Cited in the file of this patent UNITED STATES PATENTS Re.20,738 Metzger May 24, 1938 2,256,880 Goldsby et al Sept. 23, 19412,408,999 Robertson Oct. 8, 1946 2,409,544 Clarke Oct. 15, 19462,576,071 Howes et al Nov. 20, 1951

1. A PROCESS FOR CONVERTING A HYDROCARBON FEED SUP-PLY OF C3 AND C4PARAFFINS AND OLEFINS INTO GASOLINE COMPONENTS OF VARIABLE PREDETERMINEDVOLATILITY AND GOOD ANTI-KNOCK CHARACTERISTICS, WHICH COMPRISESSEGREGATING FROM SAID FEED HYDROCARBONS IN OLEFIN-RICH C3 FRACTIONCONTAINING 70 TO 95% PROPYLENE AND A C4 FRACTION CONTAINING BUTYLENESAND ISOBUTANE, FEEDING AT LEAST A PORTION OF SAID OLEFIN-RICH C3FRACTION AND WATER OF HYDRATION INTO A HYDRATION ZONE CONTAINING AHYDRATION CATALYST UNDER CONDITIONS CONDUCTIVE TO PRODUCE AN OXYGENATEDLIQUID BOILING PRINCIPALLY BETWEEN ABOUT 50* AND 95*C., RECOVERING SAIDOXYGENATED LIQUID AND AN UNCONVERTED PROPYLENE-CONTAINING FRACTION,RECYCLING A PORTION OF SAID UNCONVERTED FRACTION TO SAID HYDRATION ZONE,THEREBY ADJUSTING THE RATIO OF UNCONVERTED PROPYLENE TO PROPYLENECONVERTED TO OXYGENATED LIQUID, PASSING A SUFFICIENT PORTION OF SAID C4FRACTION THROUGH A POLYMERIZATION ZONE CONTAINING A POLYMERIZATIONCATALYST